12 Little-Known Signs of Nutrient Deficiencies Affecting Your Energy & Mood

2. Vitamin B Complex: The Energy Catalysts

The B vitamin family—B1 through B12—functions like a metabolic orchestra, each vitamin playing a distinct but complementary role in converting carbohydrates, fats, and proteins into energy. B1 (thiamine) is essential for glucose metabolism, B2 (riboflavin) helps activate other vitamins, and B3 (niacin) supports cellular respiration. B6 is crucial for neurotransmitter synthesis, influencing mood and reducing fatigue, while B12 maintains nerve health and helps form red blood cells. A deficiency in even one B vitamin can disrupt energy flow and emotional balance. Found in whole grains, meats, dairy, and legumes, B vitamins are foundational to daily energy and mental clarity.